Pressure-retaining device.



' G. 0. HAMMOND Ga J. A. BARNES.

PRESSURE RETAINING DEVICE.

APPLICATION IILED FEB. 8, 1911. 1,026,310. Patented May 14, 1912.

f? {Ii-i111 i I Z I I I i p e O ffizrre/vvcovtd flu a a 0 n 0 5 a 1 Mm 3 m a Q [y $4.5m l w rii W I i m\\ fi j UNITED STATES PATENT OFFICE.

GEORGE OVERTON HAMMOND AND JOHN ATLEE BARNES, OF WATERTOWN, NEW YORK, ASSIGNORS TO THE NEW YORK AIR BRAKE COMPANY, A CORPORATION OF NEW JERSEY.

PRESSURE-RETAINING DEVICE.

Specification of Letters latent.

Application filed February 8, 1911.

To all whom it may concern Be it known that we, GEORGE O. HAM- MOND and JOHN A. BARNES, both citizens of the United States, and both residing in \Vatertown, county of Jefferson, State of New York, have invented an Improvement 1n Pressure-Retaining Devices, of whlch the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

The present invention relates to a pressure retaining device of that class wh ch 15 used in connection with an automatic a1r brake system in which it is desirable to retain pressure in the brake cylinders 1n certain cars of the train; and, in caseswhere a train is made up of empty and loaded cars, to retain a greater pressure in the brake cylinders of the heavier loaded cars than in those of the empty or lighter cars. In valves of this class, weights have been employed to retain the pressure, the said weights resting directly on the valves to hold them seated until the pressure is suiticiently high to lift both valve and weight.

It is the purpose of the present invention to arrange the weight so that diiferent pressures are exerted thereby upon the valve for different degrees of pressure, while the weight is supported independently of the valve when the pressure retaining device is not in use. In the construction embodying the invention, the weight, instead of resting directly upon the valve, is adapted to act upon the same through a lever provided with means whereby its supporting fulcrum can be shifted from one position to another, so that the weight acts on the valve through different leverages for the purpose of retaining different degrees of pressure. The weight is also provided with means whereby it is supported independently of the valve, when the pressure retaining device is not in use, thereby relieving the valve of the continual pounding which ensues if the valve is continually acted upon by a weight. The supporting and controlling devices for the weight are connected with a suitable actuating handle which also operates a cock in the exhaust passage from the triple valve, so that by setting the handle in different positions, the exhaust may be opened directly to the air, or to the duct controlled by the pressure retaining valve, there being different positions of the handle when the exhaust is opened to the said duct, the weight controlling devices being acted upon, to determine the amount of pressure retained, by the lever in its movement from one of these p0sitions to another.

Figure 1 is a front elevation, partly in section, of a pressure retaining valve embodying the invention; Fig. 2 is a transverse section, on line w of Fig. 1, showing the pressure retaining valve out of action; Fig. 3 is a similar view showing the valve in action, and in the high pressure retaining posit-ion; Fig. 1 is a similar view showing the valve in low pressure retaining position; and Fig. 5 is a transverse section on line m of Fig. 2. 4

The pressure retaining valve 1 is shown as seated at the end of a passage 2 which is adapted to be put into communication with the exhaust port from the brake cylinder through a cock 3, shown as a tapered plug, which has a channel or pocket 4 adapted to open communication with a free exhaust port 5 leading directly to the air when the said cock is set in the position for ordinary use. In Fig. 5 the cock is shown in this position, the body of the tapered plug of the cock between the ends of the channel then closing the passage 2. The said cock is shown as provided with an actuating handle '6 which also carries a cam hub having the cam pro jections 7, 8 and 9 which operate to produce a longitudinal movement of a frame 10. In the position shown in Figs. 1 and 2, the frame 10 is in its lowest position, to which it is moved, and in which it is held, by the action of the cam 7. In this position, the said frame acts through a stem 12 113011 a lever 13 pivoted on the pin 14 within the casing which incloses the weight 15, the said weight resting upon the end of the lever 13, and being supported thereby, as shown. In this position, the pressure retaining valve is out of action, the passage 2 closed and the free exhaust port 5 open, the valve 1 itself not being acted upon by the weight, so that it is not subjected to the pounding action due to the continual jar.

When it is desired to set the valve for the high pressure retaining position, the handle (5 is moved to the left to the position indicated by the dotted line A, Fig. 1, the cam 9 then acting on the upper portion of the 10. The forked members at one end engage [ment with the fulcrum pin 18.

the weight at opposite sides of a downward projection which is adapted to engage the lever 16, while the forked members at the opposite end support a pin 133 whichengages in a slot 120 in the stem 12. The innerforked end of the lever 13 is, therefore, raised when the stem 12 is drawn down to its lowest position by the cam 7, and is thereby caused to lift and support the weight 15. The said lever 13, however, is entirely free. in all other positions of the stem, owing to the lost motion afforded by the slot 120.

The lever 16, which supports the weight when the lever 13 is released, is shown as having a pocket or recess 17 above which extends a pin or fulcrum piece 18 sup ported bet-ween the lugs 131. The said fulcrum piece is at one side of the valve 1, while the weight is at the other side thereof. The lever 16, therefore, will be acted on at one side of the valve 1 by the weight 15, and held against upward movement by the fulcrum piece 18 at the other side of the valve. A downward pressure is, therefore, exerted on the valve by the weight modified by leverage, in proportion to the distances between the fulcrum 18 and the valve, and the fulcrum 18 and the point where the weight is supported, respectively.

In order to move the valve to the low pressure retaining position, the handle 6 is moved to the position indicated by the dotted line B, Fig. 1, in which case the cam 8 acts on the lower part of the frame 10, moving the same to the position shown in Fig. 1. The stem 12 is provided with a fulcrum pin 19 which projects laterally at opposite sides thereof, and, in this position of the stem, engages forked and recessed ends -of the lever 16 which lie at opposite sides of the stem 12 below the fulcrum pin 19. The engagement of the pin 19 with the lever draws the latter downward, and as the lever rests on the valve as a pivot point, it is rocked out of engage- In this position, therefore, the pin 19 becomes the actual, fulcrum of the lever, and the downward pressure upon the valve is due to the action of the weight on the lever, modified by leverage in proportion to the distances betweenthe fulcrum 19 and the valve, and

the fulcrum 19 and the point where the weight is supported, respectively. In this case, the leverage is much less in favor of the weight than is the case in the position shown in Fig. 3, less pressure being exerted on the valve, and less pressure retained thereby.

In both of the positions of the handle last described, the body of the cock 3 closes the free exhaust port 5, and the annular channel 4; in the cock 3 opens communication between the triple valve and the passage 2 controlled by the valve 1.

To protect the valve 1 and its operating parts from dust and dirt, the said parts are inclosed in a substantially dust-tight casing 20 which is shown as bearing on the base 132 where it. is tightly clamped by means of an annular coupling 21. The upper part of the casing is provided with ribs or feathers 22 which constitute guides for the weight, while a small port 23 is formed in the wall of the casing to allow the air which exhausts past the valve 1 to escape.

Claims.

1. In a pressure ret aining device, a pressure retaining valve; a load acting on said valve to resist the pressure which tends to open the said valve; a free exhaust passage for the fluid under pressure; a cock controlling said free exhaust passage; and means for removing the load entirely from the pressure retaining valve when said free exhaust passage is open.

2. The combination with a pressure ret aining valve; of a loaded lever adapted to act on said valve; difierently positioned fulcrum supports for said lever; and means for causing said lever to be supported on said supports selectively.

3. The combination with a valve; of a lever adapted to, act on said valve; means for causing said lever to act selectively around different fulcrums; a weight adapt ed to act on said lever; and means for independently supporting said weight.

4:. The combination with a valve; of a lever adapted to act on said valve; a fixed fulcrum for said lever; a movable fulcrum V for said lever adapted by its movement to separate the lever from its fixed fulcrum; a weight adapted to act on said lever; and an independent support for said weight. 7

5. The combination with a valve; of a lever adapted to act on said valve; a fixed fulcrum for said lever; a movable fulcrum for said lever adapted by its movement to separate the lever from its fixed fulcrum; a weight adaptedto act on said lever; an independent support for said weight; and an actuating device common to said movable support and said independent fulcrum.

6..The combinationwith a valve controlling a pressure-retaining exhaust passagefrom a brake cylinder; of a cock adapted in one posltion to open a free exhaust passage, and in one or more other positlons to close the free exhaust passage and open the pressure retaining exhaust passage; a plurality of cams cooperating With said cook; a sliding frame operated by said own; a lever having a lost motion connection with said sliding frame and a fixed fulcrum; a Weight bearing on said lever; a second lever interposed between said weight and the valve; a fixed fulcrum for said second lever; and a movable fulcrum for said second lever carried by said sliding frame.

7. The combination with a valve; of a loaded lever adapted to act on said valve; a fixed fulcrum for said lever; a movable fulcrum for said lever; and means for moving said fulcrum to separate the lever from 7 its fixed fulcrum and bring said lever into cooperation with said movable fulcrum.

S. In a pressure retaining device, a pressure-retaining valve; a weight; means interposed between said valve and said Weight for varying the effectual pressure exerted by the weight on the valve; and an inclependent support for the weight.

In testimony whereof, we have signed our names to this specification in the presence of two subscribing witnesses.

GEORGE OVER'lON HAMMOND. JOHN A'ILEE BARNES.

Witnesses:

JNo. F. MALoNEY, H. G. WORKMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

